Can time travel to the past change the present?

The believers:

This represents a group of scientists that are convinced that time travel can alter
the past with all it's consequences for the history time line, present and future.
These people will be very careful when using time travel related technology,
and not do any unresponsible experiments.

Each experiment will be carefully planned and will have clear goals,
rules and safety measures, all in order not to
change the history time line.
Experiments might be used to proof their extreme theories about time and time travel.

Investigators testing the technology will try to avoid that their
experiments have negative side effects.
Ensuring responsible experiments only. This means that the future scientist
will intent to be accurate and careful in selecting a prophet,
choosing the contents of a message and formulate it clearly.
Part of the message will contain precise instructions
for the receiver on how to interpret and record the message.

Scientists that believe that time travel can have consequences for the past,
present and future will go to any length not to cause 'collateral damage' or
alterations in the history time line.